|Strong number||H3068 (Yĕhovah)|
The tetragrammaton is a sequence of four Hebrew letters that refers to the name of God. The four letters are Yod י, He ה, Vav ו, and He ה — read from right to left יהוה ←.
These are all consonants, so the sequence is unpronounceable unless missing vowels are assumed. In English, it is usually given as "Jehovah" JHVH or "Yahweh" YHVH yhwh. In ancient Hebrew speech, Vav may have been pronounced "w", being used as a vowel, and is sometimes for this reason transliterated as "w".
In the Masoretic text, the standard Hebrew text of the Old Testament, the tetragrammaton is given as Yĕhovah. This text was vowelized in the Middle Ages. Attempting to give the original pronunciation was considered sacrilegious by this time, so this pronunciation is an artifice. Jews believe that the Lord's true name is unspeakable until the arrival of the messiah and the restoration of the Temple in Jerusalem.
The word "tetragrammaton" is from a Greek word meaning "consisting of four letters."